Refrigerating machine



Patented 17, 1930 UNITED STATES PATENT OFFICE.

CHRISTIAN STEENSTRUP, Ol' SCHENECTADY, NEW YORK, ASSIGNOB TO GENERAL y ELECTRIC COMPANY, CORPORATION OF NEW YORK BEFRIGEBATING MACHINE Application ale-d December 29, 1988. Serial No. 829,108.

My invention relates to refrigerating machines and particularly to such refrigerating machines as are driven by electric motors.

The machine to which my invention is applied employs a refrigerant which boils at a relatively low temperature and is caused to pass through a cycle which consists in allowing the refrigerant in the liquid form to evaporate and thus absorb heat, compressing the va orized refrigerant, and removing the heat therefrom to cause it to condense into liquid form again, this cycle being continuously repeated during the operation of the machine. p

Such refrgerating machines are arranged to maintain a substantially constant temperature in the refrigerator box, being controlled by a thermostat. When the box reaches the proper temperature, the thermostat shuts down the refrigerating machine and when the temperature in the box rises a few degrees, the thermostat operates to start the refrigerating machine again. When the machine is started under these conditions, the load on the electric motor driving the machine may be excessive and even may be so great as to prevent the machine from starting. To avoid this condition, my invention has for its object a novel arrangement for unloading the compressor of the refri'gerating machine.

The various features of novelty which characterize my invention a-re pointed out with articularity inthe claims annexed to and orming a part of this specification. For a better understanding of my invention, reference may be had to thel ollowingdescription taken in connection with the accompanying drawing, in which Fig. 1 is a cross-'sectional view with parts broken away, of a refrigerating machine embodying my invention, Fig. 2 is a cross-sectional view in part taken on line 2-2 of Fig. 1 looking in the direction of the arrows: Fig. 3 is a erspective view of certain parts of the re igerating machine of Fig. 1, and Fig. 4 is a view looking down upon the top of the compressor.

In the drawing, an electric motor having a stator 1 and a rotating member 2 drives a compressor having an oscillating cylinder 3 'in which a iston 4 reciprocates, the drive being throug a shaft 5. The motor and 'compressor are mounted within the casing 6 which with the base 7 forms a chamber for compressed refrigerant. The motor and compressor are supported on the base 7- through springs 8. Surrounding the casing 6 is a coil of pi e 9 which forms the condenser of the re rigerating machine. This condenser is shown as a water-cooled one, a water jacket being formed b a casing 10 and the casing 6, water being circulated through the jacket by means of the pipes 11 and 12.

The cylinder 3 is mounted on trunnions 13 so that the same may oscillate. It has an intake port 14 on its upper surface. The end of the cylinder is covered by a iiap valve 15 through which condensed refrigerant is discharged. A member 16 having a passage 17 therethrough is mounted on top of' the cylinder. This member 16 is movable from the position in which the intake port opens directly into the compression chamber to a position where the intake port communicates with .the passage 17 in the member 16. The member 16 is pivoted at one end about the stud 18, the other end being connected to a plunger or piston 19 moving in the cylinder 20. The plunger 19 is biased by a spring 21 to the position where the member 16 uncovers the intake port 14 and is moved to the position where the port 14 communicates with the passage 17 in the member 16 by oil pressure admitted behind the plunger 19.

In the particular arrangement shown, oil pressure is developed by an oil pum comprislng an oscillating cylinder 22z W 'ch is mounted on a trunnion 23, and 1s held in close contact with plate 49 by a spring 50 mounted on trunnion 23. The cylinder 22 has la piston 24 therein, which 1s reciprocated by an eccentric pin on the end of the shaft 5. The cylinder of the oil pump communicates with the intake passage 25 and a discharge passage 26 formed in plate 49. The discharge passage communicates by means of passages 27 and 28 withthe piston 4 of the com ressor, so as to lubricate the same. Oil is also forced from the passa e 28 into a chamber 29. From the cham r 29 a passage 30 leads to the cylinder 20 containing the plunger 19 and to another passage 31 from which oil is supplied to the shaft 5. Oil is also forced from the passa e 31 into the passage 32 in the shaft 5. ien rthe motor is operating at normal speed, the centrifugal device 33 at the top of the motor shaftmoves into the position shown in the drawing against the tension of the spring 34 to close the passage 3'2. 111

When the machine ets below a predetermined speed, centri ugal force no longer keeps the member 33 in the position shown, it being retracted by the spring 34 so that oil will pass from the passage 32 around the cutout portion 35 of the member 33 and will escape out of the passage 36 into the receptacle 37 on to of the motor shaft. A stop 38 is provide for limitin the movement of the member 33 in bot directions of its movement. The oil which accumulates in the receptacle 37 is thrown out, when the machine gets up to speed, against the inner wall of the casing 6 and then runs down this wall into a chamber 39 formed by a member 40 and the lower portion of the casin 16. When the chamber 39 is filled witg oil, the oil overflows into the bottom of the compression chamber and any liquid sulhur dioxide carried down by the oil will be trapped in this chamber 39 and is evaporated as the machine warms up. Oil is withdrawn from the bottom of the compression chamber through an intake screen 41 which communicates with the intake passage 25 from whence it is drawn int o the cylinder on the suction stroke of the oil pump, the parts bein in the position shown in Fig. 3. As the oi pump reaches the end of the suction strokethe cylinder 22 is oscillated from the position in which the cylinder is in communication with the intake passage 25 to the position where it communicates with the discharge passage 26 and as the piston 24 of the oil pump makes its compression stroke, oil is forced through the discharge passage 26 and then into the passages 27 and 28 to lubricate the piston 4 and shaft 5 and supply oil pressure to the cylinder 20.

Communicating with the p17 in the member 16 is an intake member 42 which is movable with the member 16 and is shown as a piece of pipe having ball and socket connections with the member 16 and a member 43. The member 43 is pressed against the member 42, the member 42 against the member 16 and the member 16 ainst the top of the cylinder'3 by means o a spring 44. The member 43 is connected by a pipe 45 to an eva rator not'shown below the bass?.

vduring the suction stroke of thefpiston 4.

as the piston 4 reaches the end o the suction stroke the cylinder 3 oscillates so that the member 16 moves to the position shown Fig. 3, wherein the intake port 14 is covered y the member 16 so that it no longer communicates with the passage 17. The piaton 4 on its compression stroke com reses the as' in the cylinder and as the piston 4 reac es the end of its compression stroke, the ila valve 15 opens, permitt' the compresse as to escape from the cy nder into the in er 46 through the pipe 47. From the muler, the gas p into the comprasion chamber formed by the casing 6 and enters the condenser 9 at the top of the caaing 6. The com condenser 9 and in cooli li out of the condenser atntie through pipe 48, from whence it is supplied to the eva rator in the usual manner.

When t e machine stops or its speed is reduced below a predetermined amount, the centrifugal member 33 is retracted by spring spring 34 so that oil will pass from p 32 around cutout portion 35 of member i into the receptacle 37. In this wa the oil pressure in chamber 29 is reducedv as well as the oil pressure upon plunger 19. The springl 21 now overcomes the oil pressure nd t e plun er moves back into the cyliner. to the position s own in Fig. 4, uncovering intake port 14 so that it is in direct communication with the compression chamber. This results in ualizing the pressure on both sides of the piston as the machine slows down, and prevents vibration of the machine while stopping. Also when the motor starts again, the compressor will not compress any gas, at least not for a few strokes and not until the motor gets up to speed a in. When the motor again gets up to speen?a the centrifugal device again closes assage 32, and oil pressure is built up in c amber 29, whereupon member 16 is moved into the position where the intake port 14 communicates with passage 17 in member 16 during the suction stroke of the compressor.

When the plunger 19 is retracted into the position shown in Fig. 4, the passage 17 in member 16 is sealed or closed at one end thereof by the upper wall of the cylinder. With this arrangement, low pressure gas from the eva rator cannot enter the compression chambgr vwhile the machine is uefies, passi ttom thereo ressed gas is cooled in the" The p un r moves the member 16' pressure in the machine.

I desire it to be understood that my unloader may be-used with compressors of different construction than the one illustrated herein, and I aim in the appended claimsto` cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States,is:

1. In a refri rating machine, a compressor, a motor or driving said compressor, means formin a chamber for compressed refrigerant, said compressor havin a cylinder, said cylinder having an int e ort, a movable member having a passage t erethrough, and means for moving said movable member `from the position in which said intake port opens directly into said coin ression chamber to the position where sai iiitake port communicates with the passage in said member.

2. In a refrigerating machine, .a compressor, a motor for drivi said compressor, means formin a cham r for compressed refrigerant, said compressor having p0 a cylinder, said cylinder having an intake port, a movable member having a passage therethrou h, an intake member communicating wit the passage in said movable member, and means for moving s aid movable member from the position in which said intake port opens directly into said compression chamber ,to the position where said intake port communicates with the pass e in saidmovable member.

3. an a refrigerating machine, a compressor, a motor for driving said compressor, means forming a chamber for ccmpressed refrigerant, said compressor having a cylinder, said cylinder having an intake port, a movable member having a passage therethrough, means for buildinup an 011 pressure, and means acted upon y said oil pressure for moving said movable member from the position in which said intake port opens directly into said compression chamber to the position where said intake port communicates with the passage in said member.

4. In a refrigerating machine, a compressor, a motor for driving said compressor, means forming a chamber for compressed refrigerant, said compressor having a cylinder, said cylinder having an intake port, a movable member having a passage therethrough, an intake member communieating with the passage in said movable member, means for building up an oil pressure, and means acted upon by said 4oil pressure forymoving said movable member from the position in which said intake port opens directly into said compression chamber to the position where said intake port 4communicates with member'.

5. In a refri erating machine, a compressor, a motor or driving said compressor means for'min a chamber for compressed refrigerant, said compressor having a cylinder, said cylinder having an intake port, a pivoted movable member having a passage therethrough, means for building up ano'il pressure, a plunger biased to one position a sprin and adapted to be moved against connected to said ivoted movable mem r s o as to move sai said intake port opens directly into said compression chamber to the position where said intake port communicates with the passage in said member after oil pressure has been built up.

,6. In a refrigerat-ing machine, a compressor, a motor for driving said compressor, means forming a chamber for compressed refrigerant, said compressor having a cylinder, said cylinder having an intake rt, a movable memberrhaving a passage therethrough, means for buildin up an oil pressure, means acted upon by said oil ressure for moving said movablemember rom the position in which said intake ort opens .directly into said compression c amber to the position where said intake port communicates with the passage in said member, and means dependent on the speed on said motor for relieving the oil pressure on said last mentioned means.

7 In a refri erating machine, a compressor, a motor or driving said compressor, means forming a chamber for compressed refrigerant, said compressor havin a cylinder, said cylinder having 'an int e port, a pivoted movable member having a passage therethrough, means for building up an oil ressure, a plunger biased to one position y a spring and adapted 'to be moved against the ull of said spring by oil pressure, said p unger being connected to said pivoted movable member so as to move said movable member from the position in which said intake port opens directly into said compression chamber to the position where said intake port communicates with the passage in said member after oil pressure as been built up, `and means dependent on the speed ofsaidfmotor for relieving the oil pressure on said plunger.

8. In a refrigerating machine, a compressor, a motor .for driving said compressor, means forming a chamber for compressed refrigerant, said compressor having a cylinder, said cylinder having an intake port, a movable member having a passage therethrough, means for building u an oil pressure, means acted upon by sai oil ressure for moving said movable member romthe mv able member from the position in which" `t e pull o said spring vby oil pressure, saidplunger bein Alll inder, said cylinder havinghan inta position in which saidv intake port opens dipressor, a motor for driving said compressor rectly into said compression c amber tothe means forming a chamber for compressed position where said intake port communicates with the :s: g in said member, and means de ndent upon the speed of said motor for re 'eving the oil pressure on said last mentioned means, saidmember moving to seal one end of said passage in said movable member when said oi pressure is relieved.

v 9. In a refriv rating machine, a compres-r sor, a motor or driving said compressor, means forming a chamber for compressed' refrigerant, said compressor havin a cylinder, said cylinder having an inta e ort, a movable member having a passage t erethrough, an intake member communicating with the passa e in said movable member,

means for buil mgup an oil pressure, means acted upon by said oil pressure for moving said movable member rom the position in which said intake ort opens directly into said compression c amber to the position where said intake port communicates with the (passage in said member, and means depen ent u n thespeed of said motor for relieving e oil pressure on said last mentioned means, said member moving to seal one end of said assage in said movable member ywhen said oil pressure is relieved.

10. In a refrigera machine, a compressor, a motor for driving said compressor, means forming a chamber for compressed refrigerant, said compressor havingta cyle port,

a pivoted movable member aving a passage therethrough, means for building up an oil rassure, a plunger biased to one position by a spring and movable against the pull of said spring b oil pressure, said plunger being connecte to said pivoted movable member so as to move said movable member from the position in which said intake rt opens directly into said compression c amber to the position where said intake port communicates with the p e in said member after oil pressure n built up, and means dependent upon the speed of said motor for relieving the oil pressure on said plunger, said member moving to seal one end of said passage in said movable member when oil pressure on said plunger is relieved.

11. In a refrigerating machine, a compressor, a motor for driving said compressor, means forming a chamber for compressed refrigerant, said compressor having an oscillating cylinder, said cylinder having an vintake port a movable member having a p therethrough, and means for moving said movable member from the position in which said intake port opens directly into said compression c amber to the position where said intake port communicates with the passage in said member on the suction stroke of said compressor.

12. In a refrigerating machine, a coinrefrigerant, said com ressor having an oscillating cylinder, said cylinder having an intake ort, a movable member havi a passage t erethrough, means for building up an oil pressure, and means acted upon by said oil pressure for moving said movable member from the osition in which said intake port o ns rectly into said compression cham r to the position where said intake port communicates with the passa e in said member on the suction stroke of said compressor after oil pressure has been built up.

13. In a refrigerating machine, a compressor, a motor for drivin said compressor, means forming a cham r for compressed refrigerant, said compressor having an oscillating cylinder, said cylinder having an intake port, a pivoted movable member having a passage therethrough, means for building up an oil pressure, a plun r biased to one position by a spring an movable against the ull of said spring by oil pressure, said p unger being connected to said pivoted movable member so as to move said movable member from the position in which said intake port opens directl into said compression chamber to the position where said intake rt communicates with the"pas sage in sai member on -the suction stroke of said compressor after oil pressure has been built up.

14. In a refri rati machine, a compressor, a motor or driving said compressor, means formin a chamber for comp efri rant, said com ressor having an` oscillating cylinder, sai cylinder having an intake port, a movable member havi a passage therethrough, means for buil ng up an oil pressure, means acted upon by said oil pressure for moving said movable member from the position in which said intake port opens directly into said com ression chamber to the position where sai intake port communicates with the passage in said member on the suction stroke of said compressor after oil rassure has been built u and means depen ent upon the speed of said motor for relieving the oil pressure on said last mentioned means.

15. In a i-efrigerating machine a compressor, a motor for driving said compressor, means formin a chamber for compressed refrigerant, said compressor having an oscillating cylinder, said cylinder having an intake port, a movable member having a passage therethrough, means for building up an oil pressure, means acted upon by said oil ressure for moving said movable member rom the position in which said intake rt opens directly into said compression chiimber to the position where said intake port communicates with the passage in said member lll on the suction stroke of said compressor after oil pressure has been built up, and meansv dependent upon the speed of said motor for relieving the oil pressure on said last mentioned means, said member moving to seal one end of said passage in said movable member when oil pressure is relieved.

16. In a refrigeratin machine, a compressor, a motor for driving said compressor, means forming a chamber for compressed refrigerant, said compressor having an oscillating cylinder, said cylinder having an intake port, a pivoted movable member having a passage therethrough, means for building up an oil pressure, a plunger biased to one position by a spring and movable against the pull of said spring by oil pressure, said plunger being connected to said pivoted movable member so as to move said movable member from the position in which said intake port opens directly into said compression chamber to the position Where said intake port communicates with the passage in said member on the suction stroke of said compressor after oil pressure has been built up, and means dependent upon the speed of said motor for relieving the oil pressure on said plunger.

17. In a refrigerating machine, a compressor, a motor for driving said compressor,

v means forming a chamber for compressed refrigerant, said compressor having an oscillating cyhnder, said cylinder having an lntake port, a pivoted movable member havl ing a passage therethrough, means for building up an oil pressure, a plunger biased to one position by a spring and movable agalnst the pull of said spring by oil pressure, said plunger being connected to said pivoted movable member so as to move said member from the position in which said intake port opens dlrectly into said compression chamberto the position where said intake port communicates with the passage in said member on the suction stroke of said compressor after oil pressure has been built up, and means dependent upon the speed of saidmotor for relieving the oil pressure on said plunger, said pivoted movable member moving to seal one end of said passage in said movable member when oil pressure on said plunger is relieved.

18. In a refrigerating machine, a compressor, a motor for driving said compressor, means formin a chamber for compressed refri erant, sai com ressor having an oscillating cylinder, said) cylinder having an intake port, a movable member having a passage therethrough, said member being pivoted at one end thereof, means for building up an oil pressure, a plunger biased to one position b a spring and movable against the pull o said "spring by oil pressure, said plunger being connected to said movable member at the other endrthereof from said ivot so as to move said movable member rom the position in which said intake port opens directly into said compression chamber to the position where said intake port communicates with the passage in said member on the suction stroke of said compressor after oil pressure has been built up.

19. In a refrigerating machine, a compressor, a motor for driving said compressor, means forming a chamber for compressed refrigerant, said compressor having an oscillating cylinder, said cylinder having an intake port, a movable member having a passage therethrough, said member being pivoted at one end thereof means for building up an oil pressure, a plunger biased to one position by a spring and movable against the pull of said spring by oil pressure, said plunger being connected to said movable member at the other end thereof from said pivot so as to move said movable member from the position in which said intake port opens directly into said compression chamber to the position where said intake port communicates with the passage in said member on the suction stroke of said compressor after oil pressure has been built up, and means dependent upon the speed of said motor for relieving the oil pressure on said plunger.

20. In a refrigerating machine, a compressor, a motor for driving said compressor, means formin a chamber for compressed refrigerant, sai compressor having an oscillating cylinder,'said cylinder having an intake port, a movable member-having a passage therethrough, said member belng pivoted at one end thereof, means for bullding up an oil pressure, a plunger biasedto one position by a spring and movable against the p'ull of said spring by oil pressure, saidl plunger being connected to said movable.

member at the other end thereof from said pivot so as to movesaid movable member from the position in which said intake port opens directly into said compression chamber to the position Where sald intake port communicates with the passage in said member on the suction stroke of said compressor after oil pressure has been built up, and means dependent upon the speed of said motor for relieving the oil pressure on said plunger,` said member movlng to seal one end of said passagel in said movable member when oil pressure on said plunger is relieved.

In witness whereof, I have hereunto set CHRISTIAN STEENSTRUP.

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